NEW ORLEANS - Six current and former New Orleans police officers have been charged in connection with the killing of unarmed civilians on the Danziger Bridge in the chaotic days after Hurricane Katrina, federal law enforcement officials announced on Tuesday.

Four of them -- former Officer Robert Faulcon, Sgt. Kenneth Bowen, Sgt. Robert Gisevius and Officer Anthony Villavaso -- were charged with killing 17-year-old James Brissette and wounding four, all members of the same family.

In addition, Faulcon, who was arrested by FBI agents in Fresno, Texas, on Tuesday, was charged with shooting Ronald Madison, 40, a man with severe mental disabilities, in the back as he tried to flee. All four could possibly face the death penalty.

The four were also charged along with two homicide detectives, Sgt. Arthur Kaufman and Sgt. Gerard Dugue, with trying to cover up the shootings.

The 27-count indictment, which was handed up by a grand jury on Monday, paints a harrowing picture of the events on the Danziger Bridge on Sept. 4, 2005, when much of the city was still underwater.

But the case is just the most high-profile of at least eight incidents involving New Orleans police officers that are being investigated by federal officials.

Attorney General Eric Holder said Tuesday, "It will take more than this investigation to renew the New Orleans Police Department and to allow it to thrive."

"We've known it was coming for at least six months and suspected it was coming for a year," said Frank DeSalvo, a lawyer for Bowen. "It's not a shock. We're ready."

Eric Hessler, a lawyer who represents Gisevius, said federal officials should have considered the chaos that the police were operating in during the first few days after Katrina.

Lawyers for the other men could not be reached.

Starting in February, former police officers began to plead guilty to lesser charges in the case; five former officers and a civilian have done so to date.

Responding to a call that the police were under fire, officers drove to the bridge in a rental truck. Some were armed with assault rifles, others with a shotgun or a semiautomatic pistol.

Brissette and five members of the Bartholomew family were walking across the bridge to get food and supplies from a supermarket, the indictment reads, when the officers opened fire. Brissette was shot seven times. Susan Bartholomew, then 38, lost part of her arm. Jose Holmes, a nephew, was shot in the stomach.

Some officers then went to the other side of the bridge and found brothers Ronald and Lance Madison, who were on their way to check on a dentist's office that belonged to their brother, Dr. Romell Madison. The indictment said Faulcon shot Ronald Madison and then Bowen kicked and stomped on him as he lay dying.

"Our family has waited a long time for justice in this case," Romell Madison said. "These indictments represent another step forward towards that goal."